Method of vulcanizing rubber and the like



Patented May 112, i925 @EOMAS W. MILLER, 01' ASHLAND, OHIO.

memo or vuncnmzmo Romans. AND THE LIKE.

No Drawing.

' 'iect vulcanization in a comparatively short time and at low temperature.

More specifically, my invention aims to provide 11 method whereby an organic accelerator may be incorporated in the rubber compound during the milling operation, together with the sulphur without danger of premature vulcanization during either the milling or the celcndering operation. Heretofore it has been found that if an attempt made to form a rubber compound embodymg rubber, sulphur, an organic accelerator,

and a metallic oxide, such as oxide of zinc,

lead or lime, the result of combining these several ingredients is that, during the operation offmilling or calendering the meteriel in particular, wherein more or less heat is applied thereto, a premature vulcanization will occur, which is liable to ruin the stock. I have discovered, however, that a compound embodying the rubber, sulphur and the organic accelerator can be milled and calendared without practically any resultant premature vulcanization, and that the desired rulcai'iization can be secured by the after up- }')ll(..2lll0l1 thereto of the metallic oxide. which may be applied either in a powder upon the surface of the compound. or by subjecting the'compound when in the vulcunizing chumbcr to a current of air charged with the motullic oxide, or said metallic. oxide may be applied thereto in a liquid solutiou- \i'hilc being subjected to't-hc vulcunizing bout.

In carrying my improved method into offect, the stock first is'millcd, a proper quantity of sulphur and any suitable orgsnic'uc- 'celcretor being incorporated therein during said operation. Fluid milled stock then is calcndercd or iormcd otherwise to the desired thickness, and Drcfcrablv while the Application filed December 23, 192:2. Eerie! No. 6083751.

compound is still hot, the same may be dusted with cornstarch or the like, having mixed therewith a suitable quantity of metallic oxa ide, such as zinc, lead or lime. Or, it desired, the compound may be packed in such a mixture of cornstarch and metallic oxide.

While it is not absolutely necessary to upply the oxide while the stock is'werm, still it has been found to be advantageous, as warm stock better absorbs the desired percentage of the coating. I And I have also found that the metallic oxide may be applied to the stock while in the vulcunizing chamber and being subjected to the vulcanicing heart, by means of it current of air carrying said on ide. Or if desired, the metallic oxide Hm be dissolved in a liquid Solutiominto whicu the stock may be immersed, seid solution being brought to a temperature sufficient to effect vulcanization.

it will be understood that the compound after milling may be reformed to any de-- sired shape or siZe t hut is'to say, tothe shape of the finished article, and the metallic oxide applied thereto for the subsequent vulcsnizing step. I have found that the following formula. for the compound obtains very good rssuits, though I do not wish to be understood as limiting myself to the proportions named:

Per rent. Rubber "d; Sulphur w 3 Accelerator up. 2

Having thus fully described my invention, what I claim and desire to secure by Letters Patent, is:

l. The method f vulcunizing rubber compounds. which consists in first forming the (Oll'lpmlIlCl of rubber. sulphur and an organic accelerator. and then while subjecting the some to the vulcmriziug hczrt also subjecting it to the uction'oi a. metallic oxide.

'lhc mclhod of ulcunizing rubber compoundscontaining rubber, sulphur and an organic accelerator. which consists in applying to the exterior surface of the compound a metallic oxide, and subjecting the sumc to c vidcsmzing heat. 3. The method of vulcu-nizing rubber compounds containing rubber, sulphur and an till ill?

organic accelerator, which consists in dusting erator, then subjecting it to the action of a or packing the compound in a metallic oxide, liquid containing a metallic oxide, and and then subjecting the same to a vulcanizfinally vnlcanizin the same. ing 'heat. In testimony w ereof I hereunto affix my 6 4. The method of vulcanizing rubber comsignature. pounds, which consists in first forming the compound of rubber, sulphur, and an accel- THOMAS W. MILLER. 

